Ventilation boards for building structures



March 13, 1962 s. T. SAHLSTRCM 3,024,574

VENTILATION BOARDS FOR BUILDING STRUCTURES Filed June 8, 1959 mlmlmlmlwnun-usin- United States Patent 3,024,574 VENTILATION BOARDS FOR BUILDING STRUCTURES Sven Torgny Sahlstrtim, Enkopingsvagen 120, Sundbyberg, Sweden, assignor of one-half to Rudolf Gunnar Sahlstrom, Dalstigen, Bromma, Sweden Filed June 8, 1959, Ser. No. 818,623 Claims priority, application Sweden June 11, 1958 8 Claims. (Cl. 50-417) The present invention relates to a ventilation board for use in roofs and similar building structures which are subject to great differences between the inside and outside temperature.

Where winters are cold, damage is caused to buildings by moisture penetrating into the roof as vapour with the heated inside air if adequate ventilation from under the roofing is not provided. These conditions are aggravated in new buildings finished in the autumn when the outside temperature tends to sink progressively. As a rule, therefore, ventilation ducts will be provided as close to the roofing as possible. A satisfactory ventilation is not possible when using conventional building materials unless measures incurring great costs are taken, however. If, for instance, rigid and resistant slabs are laid outside the roof structure with a certain air space for ventilation purposes therebetween, such slabs have to be set in mortar which is expensive, and since the slabs have to be rather thick to have adequate strength there will be a certain moisture penetration into the same which may cause damage ie to the roofing.

It is an object of the present invention to provide a ventilation board which is adapted to form a ventilation space between itself and a supporting structure.

It is another object of the invention to provide a ventilation board able to withstand great compressive loads.

It is a still further object of the invention to provide a ventilation board which although being rigid enough for ease in handling is at the same time supple enough to conform to a supporting structure having uneven or broken surfaces.

Other objects, advantages and features of the invention will become apparent from the following description, reference being had therein to the annexed drawing.

FIG. 1 is a fragmentary cross section view of an embodiment of the ventilation board,

FIG. 2 is a similar view of another embodiment of the ventilation board,

FIG. 3 is a cross section view showing a step in the manufacture of a ventilation board,

FIG. 4 is a diagrammatic perspective view on a smaller scale of a ventilation board, and

FIG. 5 is a diagrammatic elevation view illustrating the laying of a ventilation board upon a supporting structure having a broken surface.

The ventilation board illustrated in FIG. 1 is composed by a layer of cardboard and a layer 11 of corrugated paper attached to the layer 10 to form with the latter an ordinary corrugated cardboard structure. The board is perforated by a great number of holes which preferably are evenly spaced and arranged in regular rows. The cardboard within the holes has not been cut clean away, and preferably the holes are formed by a pointed tool so that more or less regular skirt portions are formed at the outlet face of the board. In the holes and the skirt portions thus formed a mouldable substance such as concrete has been filled so that studs 12 have been formed which project some distance, equal for all studs, from the corrugated bottom face of the board, but are flush with its even top face. These studs 12 are a little thickened at their top end as the inlet end of the hole in the board needs must become flared, and they may also be thickened at their bottom end as illustrated in FIG. l. The thickened portions of the studs help to secure the latter axially.

The board is impregnated with asphalt either before the moulding of the studs or after; the former alternative is less expensive than the latter.

In FIG. 2 a preferred embodiment of the ventilation board is illustrated. This board is stiffer and easier to handle than the board illustrated in FIG. 1, and comprises a corrugated paper layer 11 covered at both sides with an even layer 10 and 13 of cardboard and paper, respectively. In other respects the boards illustrated in FIGS. 1 and 2 are quite similar.

The material forming the studs may penetrate somewhat in between the different layers of the board that.

which will serve to further secure the studs axially.

It is important that the top face of the finished board should be even and without apertures. If roofing is to be laid on top of the boards the latter should have as even a surface as possible, and furthermore, as the boards are covered with a layer of asphalt before the roofing is laid, there should be no apertures in the board through which the asphalt might escape, as might also the concrete in such cases where the ventilation boards are to be covered with a layer of concrete, for instance when the building structure has to support the load of vehicles.

The boards are preferably manufactured in a-machine for making corrugated cardboard; such machines are well known in the art, and need not be specifically described herein.

In the next step the boards are perforated, preferably with a pointed tool 14 and a corresponding die 15, FIG. 3. Naturally, a great number of tools 14 and corresponding holes in the die 15 may be provided so that a whole board or a great portion thereof may be perforated at a time. There might be about 800 holes per square metre of board, thus about holes per sq. foot.

When the tool 14 penetrates through the board the material is broken through and forced aside so that skirt portions 10a, 11a and 13a are formed (FIGS. 1 to 4), and the said skirt portions will serve as moulds for the studs 12.

The board is impregnated after having been perforated, as already described.

In the next step the board is placed in a machine of a known kind, such as used for the manufacture of hollow concrete slabs into which the concrete is fed and vibrated so that the moulds in the board are filled with concrete.

When the concrete has hardened the ventilation board is ready for use.

As an alternative the perforated board may be placed in its desired position in the building structure resting upon the skirt portions of the holes, and the concrete may be filled in afterwards and will form the studs 12.

In FIG. 4 a ventilation board of the composition illustrated in FIG. 2 is shown in a perspective view. As will be seen from the figure the studs 12 are arranged in regular rows, and this arrangement is preferred since the board often must be laid upon a structure 16 the surface of which is broken, FIG. 5. The board then is simply folded between two rows of studs to the desired shape. If the surface of the supporting structure should be uneven the board is supple enough to conform thereto so that all the studs will rest against the supporting surface.

The studs may be formed by another material than concrete, e.g. plastics, certain resins or hard asphalt. In

Patented Mar. 13, 1962 the supporting structure. The projecting portions of the studs will normally be about half as long as the diameter of the holes.

If the ventilation boards are used for roof structures suitable roofing materials are laid upon the same.

The provision of a vehicle supporting structure upon ventilation boards according to this invention is perfectly possible since the ventilation boards are able to support heavy loads.

The boards may of course be composed of more layers than described and illustrated, and of those layers more than one may be corrugated.

On the other hand, the board may comprise only one single sheet of cardboard or like material, and in that sheet holes are made with a pointed tool as described so that skirt portions are formed which serve as a mould when forming the studs of a mouldable and compressionload resistant material.

Also in other respects the ventilation board may be modified within the scope of the appended claims.

What I claim is:

1. Ventilated building structure comprising a ventilating board in combination with an underlying supporting building surface, said ventilating board being coextensive in area with said supporting building surface and being perforated throughout its area establishing a plurality of spaced apertures each of which is surrounded by a depending skirt portion of the material from which said ventilating board is constituted, said skirt portions projecting beyond all remaining surface portions of that face of the board from which said skirt portions are formed, and cast studs of rigid material received respectively within said apertures and in contact with said skirt portions, the terminal ends of said studs also projecting beyond all remaining surface portions of that face of the board from which said skirt portions are formed, said stud ends contacting said underlying building surface and supporting said ventilating board in spaced relation to said underlying building surface thereby establishing a series of communicating passageways between said ventilating board and underlying building surface.

2. Ventilated building structure as defined in claim 1 wherein said ventilating board comprises a yieldable material enabling the same to conform to any unevenness which may exist in said underlying building surface.

3. Ventilated building structure as defined in claim 1 wherein said ventilating board is composed of paper material impregnated with an impermeable substance such as asphalt.

4. Ventilating building structure as defined in claim 1 wherein said cast studs are constituted by concrete.

5. Ventilated building structure as defined in claim 1 wherein said ventilating board is composed of a paperboard material impregnated with asphalt and said cast studs are constituted by concrete.

6. Ventilated building structure as defined in claim 5 wherein said paperboard material is comprised of a plane paperboard layer and a corrugated paperboard layer.

7. Ventilated building structure comprising a ventilating board in combination with an underlying supporting building surface, said ventilating board being coextensive in area with said underlying building surface and comprising an intermediate layer of corrugated paperboard faced on each side with a layer of plane paperboard, said paperboard layers being impregnated with asphalt and said ventilating board being perforated throughout its area establishing a plurality of spaced apertures each of which is surrounded by a depending skirt portion of one of said facing layers of plane paperboard, said skirt portions projecting beyond all remaining surface portions of said plane paperboard layer from which said skirt portions are formed, and concrete studs received respectively within each of said apertures and in contact with said skirt portions, the terminal ends of said concrete studs also projecting beyond all remaining surface portions of said facing layer of plane paperboard from which said skirt portions are formed, said ends of said studs contacting said underlying building surface and supporting said ventilating board in spaced relation to said underlying building surface thereby establishing a series of communicating passageways between the surface of said ventilating board and underlying building surface.

8. Ventilated building structure as defined in claim 1 wherein the terminal ends of said cast studs project laterally beyond said skirt portions to secure said studs axially.

References Cited in the file of this patent UNITED STATES PATENTS 1,205,360 Casse et al. Nov. 21, 1916 1,268,802 Schumacher June 4, 1918 1,281,453 White Oct. 15, 1918 1,298,411 Sexton Mar. 25, 1919 2,308,942 Teasdale Jan. 19, 1943 2,387,342 Olsen Oct. 23, 1945 FOREIGN PATENTS 457,593 Great Britain 1936 203,082 Switzerland 1939 

